Traditional Controller Area Network (CAN) protocol utilizes a Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) technique similar to that of Ethernet but with frames that are relatively small by networking standards in that the largest possible frame may be around 128-bits (i.e. 16-Bytes, including the maximum of 8-bytes for the payload), whereas the Ethernet Frame varies between 64-bytes and 1,536-bytes. Unlike Ethernet however, there is no loss of data as a result of collisions. This is because of CAN's unique non-destructive message arbitration methodology that guarantees high priority messages access to the CAN bus with no fear of collision or loss of data; hence, no need for retransmission.
However, the same feature that is CAN's strength (its non-destructive collision resolution methodology) is also its weakness in that as a CAN bus approaches its utilization capacity so does its propensity for indefinite starvation of lower priority messages. Given that a CAN message cannot arbitrarily change its priority; the CAN protocol is completely inflexible under heavy loads for successfully ensuring that lower-priority messages reach their destination. The traditional methodology as known in the art for resolving this problem has been in the separation of CAN nodes into multiple CAN sub-networks. However, such delineation can often be the source of frustration when attempting to discern the most efficient means for dividing the devices into disparate CAN networks while still affording cross network communication through various backhaul communication technologies. Embodiments presently disclosed provide security and reliability within a network, while maintaining CAN's distributed network communication methodology and implicit avoidance of single points of failure within the network.
In the following description, like reference numbers are used to identify like elements. Furthermore, the drawings are intended to illustrate major features of exemplary embodiments in a diagrammatic manner. The drawings are not intended to depict every feature of every implementation nor relative dimensions of the depicted elements, and are not drawn to scale.